Open-ended questions in research: how to write and analyse them

Open-ended questions let respondents answer in their own words, generating rich qualitative data. Learn when to use them, 7 principles for writing good ones, and how to analyse the responses.

Cover Image for Open-ended questions in research: how to write and analyse them
Share this article:

An open-ended question invites respondents to answer in their own words rather than selecting from predefined options. Unlike closed questions, they generate qualitative data: text that captures reasoning, nuance, and context. Open-ended questions are used in interviews, surveys, and focus groups wherever depth matters more than scale. Analysing the responses requires qualitative coding — systematically labelling segments of text — though AI tools like Skimle can now handle that process across hundreds or thousands of responses simultaneously.


What are open-ended questions?

An open-ended question is one that cannot be answered with a yes, no, or selection from a list. It asks respondents to construct an answer in their own words. "What made you decide to leave?" is open-ended. "Did salary influence your decision to leave?" is closed.

The distinction matters for the data you get. Closed questions produce numbers — ratings, yes/no counts, frequencies. Open-ended questions produce text — reasoning, stories, nuance, and sometimes things the researcher did not anticipate asking about.

The practical trade-off is between scale and depth. A survey of 10,000 respondents using closed questions produces statistically powerful comparisons. A survey of 10,000 respondents with a single open-ended question produces a volume of text that is only manageable with systematic analysis — either through careful manual coding or AI-assisted tools. Skimle handles that volume in minutes: upload the raw responses and thematic analysis runs automatically, with every theme linked back to the individual answers that support it. For teams that want to move beyond the static open-ended question entirely, Skimle Ask replaces it with an AI interviewer that probes, follows up, and adapts to each respondent — producing the depth of a one-to-one interview at survey scale.

When should you use open-ended questions?

Open-ended questions are most valuable when:

You do not know in advance what answers look like. If you are exploring a new topic, product, or experience, closed questions force respondents into categories you invented before you understood the problem. Open questions let respondents tell you what matters to them.

The nuance between responses matters. Two employees might both rate their job satisfaction as 3/5 for entirely different reasons. One is dissatisfied because of poor management; the other because the work itself has become routine. The number hides the distinction. An open-ended follow-up reveals it.

You want to understand motivation and reasoning. "How satisfied are you?" measures satisfaction. "What would make this product significantly better for you?" generates actionable insight.

You are running an interview or focus group. Interviews are almost entirely composed of open-ended questions. The interview guide provides structure, but the questions themselves invite the participant to elaborate.

When should you use closed questions instead?

Closed questions are more appropriate when:

  • You need to compare responses across a large sample with statistical precision
  • The relevant response categories are already well-understood
  • Response burden needs to be low (open-ended questions take longer to answer)
  • You are measuring a quantifiable construct (satisfaction, likelihood to recommend, frequency of behaviour)

Many good surveys combine both. Closed questions measure; open-ended questions explain. A net promoter score survey, for example, pairs the 0-10 closed rating with "What is the main reason for your score?" — which is the question that drives action.

7 principles for writing good open-ended questions

1. Ask one thing at a time. "What did you find valuable, and what would you change?" is two questions. Respondents will answer whichever part interests them more, and you will lose the other half. Split it.

2. Avoid leading language. "Why is the experience so frustrating?" presupposes frustration. "How would you describe the experience?" does not. Leading questions corrupt your data by suggesting the answer.

3. Use plain language. Questions that require parsing — long subordinate clauses, technical vocabulary, double negatives — produce lower-quality responses. Write the question you would say out loud in conversation.

4. Specify the scope. "How was the experience?" could mean the entire relationship with the company or just the last interaction. "How would you describe your experience during the onboarding process?" is specific enough to produce comparable responses.

5. Make it genuinely open. "Would you say the product was helpful?" invites a yes or no. "How has the product affected your work?" is open. Check that your phrasing does not inadvertently close the question.

6. Sequence them appropriately. In an interview or survey, move from general to specific. Start with broad context questions before narrowing to specific experiences. Starting with a difficult or sensitive question before rapport is established produces defensive or shallow answers.

7. Anticipate the analysis. Before writing a question, ask yourself: how will you code the answers? If the question is so broad that any answer is valid, it will be difficult to extract consistent signal. "Tell me about your life" produces narrative data; "What factors most influenced your decision to stay with the company?" produces material that can be systematically coded.

How do you analyse open-ended responses?

The analysis of open-ended responses is a qualitative coding exercise. The core steps are:

Read through a sample. Before coding anything, read 20-30 responses to get a feel for the range of content. This shapes your coding approach.

Develop an initial codebook. Based on your reading and your research questions, create a first draft of codes — descriptive labels for the themes you expect to find. Leave room for codes that emerge from the data.

Code the responses. Apply your codes to each response, labelling the segments of text that are relevant. Some responses will receive one code; others will receive several.

Consolidate and theme. After coding all responses, group your codes into themes — higher-level patterns that capture the main findings. This is the interpretive step that turns labelled text into insight.

Count if useful. For large response sets, frequency counts — how many respondents mentioned each theme — add a useful quantitative layer. But count after interpreting, not instead of it.

For detailed guidance, see how to analyse employee survey open-ended responses and how to analyse open text responses at scale.

How does AI change the analysis of open-ended responses?

The bottleneck in open-ended response analysis is volume. A customer satisfaction survey with 2,000 responses and one open-ended question produces roughly 40,000-80,000 words of text. Reading and coding that manually takes days. The same dataset in Skimle is coded in minutes.

The practical workflow:

  1. Upload responses (as a CSV, document set, or direct text input)
  2. Run automatic thematic analysis to generate an initial set of codes and themes
  3. Reviewer examines themes, challenges or merges where needed, adds codes the AI missed
  4. Slice by metadata variables — by customer segment, region, survey wave — to compare patterns across subgroups

The resulting analysis is systematic, documented, and traceable. Every theme links back to the responses that support it, which makes the findings verifiable and the method auditable.

Customer and market researchers running regular customer satisfaction or NPS programmes find this workflow particularly useful: the same process applied consistently across survey waves produces comparable results over time.

HR and people teams running engagement surveys with open-ended questions can move from raw responses to thematic findings in hours rather than weeks, which changes what is feasible between survey administration and action planning.

For teams looking to go further than static open-ended questions, Skimle Ask takes a different approach entirely: rather than asking a fixed question and analysing the responses afterwards, it conducts a short AI-powered conversational interview with each participant. The AI follows up on interesting answers, asks for specifics when a response is vague, and adjusts its questions based on what the participant has already said — generating richer data than any static question can. This is particularly useful for continuous customer research, product discovery, and employee listening programmes where you want genuine dialogue at scale. See always-on customer research with AI interviews for how teams embed this into their regular research cadence.

What are the most common mistakes with open-ended questions?

Collecting data without a plan to analyse it. Open-ended questions added as an afterthought to a large survey generate data that no one has time to read. Design the question knowing how you will analyse it.

Treating word frequency as analysis. A word cloud showing that "communication" appears frequently in employee survey responses tells you almost nothing. The question is whether communication is mentioned positively ("we have great communication") or as a problem ("communication is the main thing we need to fix"). Frequency counts without coding miss this entirely.

Using too many open-ended questions in a survey. More than two or three open-ended questions in a survey significantly increases dropout rates and response burden. Be selective. One well-designed open-ended question at the end of a survey often generates more useful data than four poorly placed ones.

Analysing open-ended responses separately from the rest of the data. Open-ended responses gain meaning when connected to the closed-question data from the same respondent. The participant who rated satisfaction as 2/5 and explained "the product keeps crashing" is a different data point from the participant who rated 4/5 and mentioned the same issue. Integrate your analysis.

Frequently asked questions

How many open-ended questions should a survey have?

For most surveys, one to three open-ended questions is the practical maximum before completion rates drop. The most useful placement is at the end, after closed questions have already committed the respondent. A single well-crafted open-ended question — "What one thing would most improve your experience?" — often generates more actionable insight than multiple vague ones.

What is the difference between open-ended and probing questions?

Open-ended questions introduce a topic; probing questions deepen the response. "What has been your biggest challenge this year?" is an opening question. "Can you tell me more about that?" or "What made that particularly difficult?" are probes. Probing is essential in interviews and focus groups, where the initial answer is rarely the most revealing one.

Can open-ended survey questions be analysed quantitatively?

The responses themselves are qualitative (text), but you can attach quantitative measures to your analysis. Coding responses and counting how many responses fall into each theme introduces a quantitative layer. Sentiment analysis assigns a positive/negative/neutral score to each response. These approaches add measurability but do not replace interpretation.

How long should an open-ended question response be?

This depends heavily on the context. Survey responses to open-ended questions average 20-60 words. Interview responses to a single question might run to several minutes of speech. Longer is not always better: a concise, specific response to a well-framed question is more useful than a long, rambling answer to a vague one. Question design drives response quality.


Ready to analyse your open-ended responses at scale? Try Skimle for free — systematic thematic analysis across hundreds of survey responses, with findings traceable to individual answers.

Related reading:


About the authors

Henri Schildt is a Professor of Strategy at Aalto University School of Business and co-founder of Skimle. He has published over a dozen peer-reviewed articles using qualitative methods, including work in Academy of Management Journal, Organisation Science, and Strategic Management Journal. His research focuses on organisational strategy, innovation, and qualitative methodology. Google Scholar profile

Olli Salo is a former Partner at McKinsey & Company where he spent 18 years helping clients understand the markets and themselves, develop winning strategies and improve their operating models. He has done over 1000 client interviews and published over 10 articles on McKinsey.com and beyond. LinkedIn profile


Sources

Dig deeper to your data with Skimle

Skimle collects, analyses and categorises interviews, survey responses, reports and other qualitative data automatically. Our modern qualitative analysis software combines a rigorous and transparent workflow with the speed of AI.

Upload text or audio, remove sensitive data with Skimle Anonymise, automatically create categories and sub-categories, explore the data across documents and export the data to seamlessly fit your workflow. Built by professionals for professionals, with full privacy and GDPR compliance.

Free trial · No credit card required · Full plans from €20/month